1. Field of the Invention
The present invention relates to a control panel having a sheet-formed pushbutton unit produced by forming a general-purpose sheet and also relates to a method of producing the control panel. More particularly, the present invention relates to a control panel having a sheet-formed pushbutton unit constructed of a formed sheet prepared by thermoforming a thermoplastic synthetic resin sheet and also relates to a method of producing the control panel.
2. Discussion of Related Art
With the recent spread of equipment related to computers and communications equipment, it has been demanded that data input units, e.g. control panels, for entering information into such equipment and receiving information therefrom should be reduced in cost to an extreme without sacrificing the operability. On the other hand, the achievement of high-precision electronic parts demands hermeticity for providing a dustproof structure and for preventing breakdown of electronic parts due to static electricity. For example, control panels used in electronic equipment, e.g. portable telephones, are required to accomplish ultimate cost reductions in order to allow these electronic devices to spread at reduced costs. Moreover, the control panels are required to improve in various mechanical and electrical functions as stated above.
To meet the demands, the present applicant proposed a control panel for electronic equipment using a sheet (see Japanese Patent Application Unexamined Publication (KOKAI) Nos. 9-259696 and 9-259697). In the proposed control panel, a mechanical assembly structure is used for the assembly of a control panel member and pushbuttons. The use of the mechanical assembly structure causes the structure of the control panel to become complicated and also causes the number of components to increase.